Robinson's Phase Lag ~ The true story.
Look! its real simple. That rotor head design gets round a number of problems, but there is nothing magic about the phase lag. A rotor head that has this digree of freedom will only work at a certain phase lag and remain controllable (just) and that is the one the designer settled on and has stuck with. If the 44 is slightly different its because the bigger blades and different speeds dictated what the phase angle needed to be on this machine. These machines have a self centering rotor system and that why the rotor balance is a bugger and the main reason that when it gets into an out of balance situation however caused it is catastrophic.